A union leader for Boston school bus drivers who was fired after a one-day strike in October is now facing criminal charges over an alleged assault last month on a manager for the private contractor that operates school buses for the city.
Police allege that Stevan Kirschbaum, 61, of Roslindale, pushed a table against a Veolia Transportation manager as union members rallied June 30 at a school bus yard in Dorchester.
Kirschbaum pleaded not guilty Monday in Dorchester District Court to charges of assault and battery with a dangerous weapon, breaking and entering during the daytime, malicious destruction of property over $250, and trespassing.
On the day of the alleged incident, the drivers and their supporters had gathered at the bus yard to discuss contract negotiations with Veolia, according to union officials. Their contract expired that day.
“It’s a labor dispute. I don’t think it belongs in court,” said Kirschbaum’s lawyer, Barry P. Wilson. “I think the company should be more concerned with negotiating with the union instead of bringing frivolous charges against Mr. Kirschbaum.”
During the union gathering on Freeport Street, police allege that Kirschbaum was among a group that broke through locked doors and entered a Veolia facility about 8:30 p.m., according to a police report filed in the court.
After the crowd broke through doors leading to the front of the building, Angela Griffin attempted to place a table in front of the entrance to the main portion of the building and told those gathered that the building was closed and they couldn’t enter, the police report said.
Kirschbaum allegedly responded, “Oh, we’re coming in,” and pushed the table against Griffin, striking her in the legs and causing her to stumble, the report said.
Wilson said Kirschbaum didn’t assault anyone and that doors to the facility were open. He filed a motion seeking to have the case remanded to a clerk magistrate for a hearing.
Kirschbaum was released on his own recognizance and then spoke to supporters outside the courthouse. Among them were City Councilor Charles Yancey; Charles Clemons, a past mayoral candidate; and former city councilor Chuck Turner, who was convicted in a 2010 federal bribery case.
“We’re going to put Veolia on trial,” said Kirschbaum, who called the allegations “crazy frame-up charges.” He is due back in court on Sept. 15.
Kirschbaum was among four bus drivers who were fired last November after United Steelworkers Local 8751 staged a surprise one-day strike that stranded thousands of schoolchildren.
All the fired drivers held leadership positions with the union, said Alfred Gordon O’Connell, a lawyer who represents the union on arbitration matters involving the drivers.
In a prepared statement, Veolia said, “This was a very troubling incident that occurred. It is now in the hands of the Boston Police and the courts and we will leave the resolution of the matter to them.”
Kate Norton, a spokeswomen for Mayor Martin J. Walsh, said negotiations with the union are continuing and that the two sides have agreed to extend the expired contract on a day-to-day basis.

John R. Ellement of the Globe staff contributed to this report. Laura Crimaldi can be reached at laura.crimaldi@globe.com. Follow her on Twitter @lauracrimaldi.